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Sieyuan commissioned 182 oil-free, gas-free RIP dry-type bushings rated up to 420 kV on IPTO autotransformers in Greece.
420 kV RIP Bushing Solution Supporting Greece's Major Grid Project
Sieyuan Electric has successfully commissioned its independently developed resin-impregnated paper (RIP) dry-type bushings, rated up to 420 kV, at a key substation of Greece's Independent Power Transmission Operator (IPTO). The project comprises 20 sets of 280 MVA/400 kV three-phase autotransformers. Sieyuan supplied RIP bushings for 17 units, including 55 rated 420 kV, 55 rated 170 kV, 17 rated 126 kV, and 55 rated 52 kV. The oil-free and gas-free RIP capacitive design provides flame-retardant and explosion-resistant performance with a maintenance-free configuration, meeting the project's requirements for safety, reliability and environmental performance.
Project Overview
Sieyuan commissioned 182 oil-free, gas-free RIP dry-type bushings rated up to 420 kV on IPTO autotransformers in Greece.
Project Background
A major 420 kV Greek grid expansion with demanding qualification and delivery requirements.
Key Challenges
A compressed schedule alongside seismic, pollution and artificial-ageing qualification.
Sieyuan Solution
A dedicated execution plan delivering all 17 transformer sets in five months EXW.
Technical Highlights
Oil-free RIP construction, composite external insulation and low partial discharge.
Project Overview
Project Background
The project is a major 420 kV grid construction and expansion project in Greece, with demanding delivery and technical qualification requirements. The bushings required verification and supporting documentation covering seismic performance, insulation under polluted conditions, and weathering and tracking resistance of the silicone rubber housings.
Key Challenges
- Compressed delivery schedule — RIP bushings for 17 main transformers had to be delivered within a limited timeframe to support the overall project schedule.
- Comprehensive qualification requirements — The project required seismic calculation reports based on structural dynamic analysis, artificial pollution test reports, and verification of silicone rubber housings for weathering and tracking resistance in accordance with applicable IEC standards and Greek grid requirements.
- Enhanced factory quality control — Additional factory testing included prolonged partial discharge assessment under specified voltage conditions and temperature-rise testing under terminal mechanical loading on sampled units.
Sieyuan Solution
- Rapid project execution — Sieyuan coordinated design, verification, manufacturing, testing and delivery through a dedicated project execution plan. All RIP bushings for the 17 main transformers were delivered with an EXW lead time of just five months, supporting the project construction and commissioning schedule.
- Comprehensive performance verification — The products were supported by technical documentation and verified against applicable IEC standards and project requirements, including seismic and insulation performance.
Technical Highlights
- Oil-Free and Gas-Free RIP design — The dry-type RIP capacitive structure eliminates insulating oil and gas, providing flame-retardant and explosion-resistant performance with a maintenance-free design.
- Reliable insulation performance — Composite external insulation provides resistance to pollution flashover and aging. Automated winding, vacuum drying, impregnation and curing processes ensure a dense and uniform internal insulation structure with low partial discharge.
- Reliable current-carrying and sealing design — Cable-through and conduit configurations accommodate different installation requirements. A multi-stage sealing structure helps prevent moisture and dust ingress, supporting reliable long-term operation.
